where \(\Delta _{A^{m+1}}(\lambda ^{m+1})\)  is a Fredholm determinant of the operator \(A^{m+1}\)  (see [1]}).
In accordance with Theorem 11 [2]}, we have
\(\Delta _{A^{m+1}}(\lambda ^{m+1})\ge e^{-(2+\ln \lbrace 12e/\delta \rbrace )\ln \xi _{m}},\;\xi _{m}= \!\!\!\max \limits _{\psi \in [0,2\pi /(m+1)]}\lbrace \Delta _{A^{m+1}}([2e \tilde{R}e^{i\psi }]^{m+1})\rbrace ,\) 
